Cellular Communication System: Overview Pontiac Aztek I

Test Description

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Lack of communication may be due to a partial malfunction or a total malfunction of the class 2 serial data circuit. The specified procedure will determine the condition.
2. 5. The presence of DTCs which begin with "U" indicate some other system control module is not communicating.

The number below refers to the step number on the diagnostic table.

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1. 2. This step checks that the Vehicle Communication Interface Module is sending out the proper supply voltage.

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. This step checks the condition of the cellular and navigation antenna.
2. 3. This step tests the condition of the cellular antenna coax and for proper ground of the cellular antenna.

The number below refers to the step number on the diagnostic table.

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1. 2. This step checks that the Vehicle Communication Interface Module is sending out the proper supply voltage.

The number below refers to the step number on the diagnostic table.

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1. 2. This step tests the at rest state of the Keypad Signal circuit.

System Description

This symptom table will enable the user to verify the customer complaint and narrow it to its source. If there is a concern with voice recognition or OnStar® steering wheel control function, technicians should proceed directly to the applicable diagnostic in SYMPTOMS - CELLULAR COMMUNICATION .

Important: To successfully diagnose and repair the OnStar® system it is necessary to comprehend its operation. Technicians should read and understand the ONSTAR DESCRIPTION AND OPERATION before attempting to repair an OnStar® system.

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1. The customer concern may have been due to a lack of cellular service in a given area or a failure in the National Cellular Network infrastructure that has since been corrected.
2. If the prompt OnStar request ended is heard without pressing the white dot button at the end of an OnStar® key press, the OnStar® system at one time has made a successful cellular connection, but was unable to complete the call. If repeated calls are placed with this result, contact the General Motors Technical Assistance Center.
3. Inaccurate or aged global positioning system (GPS) position may have been due to the temporary loss of GPS signal reception by the vehicle in instances such as driving through tunnels or parking structures which restrict the navigation antenna from a clear view of the satellites in the sky.

Symptoms - Cellular Communication

Important: The following steps must be completed before using the symptom tables.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - CELLULAR COMMUNICATION»(ref-180863-S01358686682005073000000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control module can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «ONSTAR DESCRIPTION AND OPERATION»(ref-180863-S32825192092005073000000) .

The numbers below refer to the step numbers on the diagnostic table.

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1. 3. Determines if the OnStar® status LED has the necessary Green LED signal circuit voltage.
2. 5. If the Green LED signal is shorted to voltage then the OnStar® three button assembly has been damaged and the OnStar® three button assembly must be replaced.

The number below refers to the step number on the diagnostic table.

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1. 7. If the Remote Radio Audio Output (--) circuit is shorted to voltage the Vehicle Communication Interface Module has been damaged and requires replacement.

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1. If the OnStar® Call Center has not received any GPS data, this is an indication that the OnStar® call was a fail to voice and may be due to a failure in the National Cellular Network infrastructure. If this occurs, contact the General Motors Technical Assistance Center.
2. Inaccurate or aged GPS position concerns made by a customer which are no longer present may have been due to the temporary loss of GPS signal reception by the vehicle. Conditions such as driving through tunnels or parking structures while making an OnStar® key press will restrict the navigation antenna from a clear view of the satellites in the sky and may have caused this temporary data loss.

OnStar® Description and Operation

This vehicle uses the Generation 5 version of the OnStar® system. This system consists of the following components

1. Vehicle communication interface module (VCIM)
2. OnStar® button assembly
3. Microphone
4. Cellular antenna
5. Navigation antenna

This system also interfaces with the factory installed vehicle audio system.

Operation Of Hands Free Cellular Phone

OPC operates similar to most hand held cellular phones in that the availability for its usage is based on minutes or "units". The customer must have a current OnStar® subscription, as this feature cannot be utilized without it. To use OnStar® Personal Calling, the customer must also purchase units as outlined in the owners guide provided with the OnStar® system. When the customer purchases minutes, an OnStar® advisor "loads" these minutes into the VCIM over the airwaves at the time of the request, or through a discrete cellular call to the vehicle at a later time. Once loaded into the module, the units may be used for non-international, outbound cellular phone calls and connection with the OnStar® Virtual Advisor. Units begin to deplete (one unit is equal to one minute) as the customer makes outbound phone calls, answers inbound phone calls, or while connected to the OnStar® Virtual Advisor. In addition, units also have an expiration date, depending upon the type of units purchased. This date is established when the download is performed and any remaining units expire when the date within the VCIM (which is based on current date and time transmitted by GPS satellites) has passed. At any time, the user can press the answer/end call button, say "Units" and verify the number of units remaining.

During a hands free call, the microphone and audio system operate the same way as a standard OnStar® call. When the answer/end call button is pressed, the audio system will mute; the OnStar® system will then return the prompt "OnStar Ready". At this point there are specific commands set to initiate a cellular call. If the vehicle receives a call when the radio is on, the audio system will mute and an audible ring will be heard though the speakers. The call will be answered when the answer/end call button is pressed.

The Vehicle Communication Interface Module interprets all of the voice-activated commands. A complete list of these commands is supplied in the information provided to the customer. If the information is not available to reference, at any command prompt the caller can say "HELP" and the VCIM will return an audible list of available commands. If the customer concern is not being understood or not being heard by the OnStar® system, the user should place a call to the OnStar call center to verify proper operation of the microphone. Following this description is an example of the commands and the OnStar system responses. A complete list of commands is supplied in the information provided to the customer with the OnStar® system.

Mobile Identification Number and Mobile Directory Number

The Generation 5 VCIM utilizes two numbers for cellular device identification, call routing and connection, a MIN (Mobile Identification Number) and a MDN (Mobile Directory Number). The MIN represents the number used by the cellular carrier for call routing purposes while the MDN represents the number dialed to reach the cellular devise. Although technicians have the capability to change these numbers by means of the scan tool, this should ONLY be done at the direction of and with explicit instruction from the General Motors Technical Assistance Center (GM TAC).

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Operation of the OnStar® Speech Recognition Systems

OnStar® Generation 5 users communicate with 2 speech recognition systems. Speech recognition allows the user to speak to one computer in the vehicle, and one reached over a phone line. The computer tries to understand the user's command, and responds by speaking back, or by taking the appropriate action, e.g. dialing the phone.

1. Personal Calling uses a speech recognition system that resides in the vehicle. When the user presses the dot button, the system states, Ready, and listens for the user's command. The user can speak commands to control the hands-free phone.
2. Virtual Advisor is a remote speech recognition system that the caller access by making a phone call. The user connects to Virtual Advisor by requesting it during personal calling use. The user is then transferred to the Virtual Advisor server and talks to it via a cellular connection

The OnStar® speech recognition systems use speech technology that is designed to understand a wide range of American English speakers. Although there is no one right way to speak English, the system will work best when users try to modify their pronunciation should they encounter difficulty. Users who do not obtain good results are advised to try the tips and workarounds found in this section.

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